The Impact of Psychiatric History and Peri-operative Psychological Distress on Weight Loss Outcomes 1 Year After Bariatric Surgery.

Background: To determine if self-reported baseline psychological distress moderates the association between lifetime psychiatric diagnosis and weight loss 1 year after bariatric surgery. An exploratory analysis assessed change in psychological distress from baseline on weight loss at 1 year.

Methods: A retrospective cohort study using data from the Ontario Bariatric Registry for all individuals undergoing surgery between January 1, 2012, and December 31, 2018, with a complete baseline psychological assessment and 1-year post-operative weight recorded (N = 11,159). Multiple linear regressions assessed the relationship between psychiatric diagnosis and percentage of excess body mass index loss (%EBMIL) at 1-year post-surgery, controlling for baseline body mass index, socio-demographics, medical co-morbidities, and surgical complications. Baseline psychological distress, measured with the EQ-5D-5L anxiety/depression rating, was examined as a moderator of this relationship. %EBMIL was separately regressed on change in psychological distress from baseline to 1 year, controlling for psychiatric diagnosis.

Results: In the adjusted model, psychiatric diagnosis was associated with lower %EBMIL at 1 year (B =  - 1.00, P = .008). Baseline psychological distress was not a moderator, but had a significant main effect on %EBMIL (B =  - .84, P = .001). Those who experienced a decrease in psychological distress at 1 year, or remained low throughout, fared better than those who increased or had persistently high symptoms.

Conclusions: These findings support use of a self-report assessment for psychological distress prior to bariatric surgery. Addressing active psychological distress prior to and/or following surgery may increase the likelihood of successful outcomes.